Why aren't my OLE data source data queried?

Question

I have a Microsoft Excel 2003 file that I am requesting from C # 2.0 using OleDbConnection.

One of the cells in the Excel file is formed as a short date and displayed in Excel as "1/1/2009". If I change the format to general, the text displayed in this cell will change to "39814".

If I query the Excel file when the file is open , I get "39814" in the result set.

If I request the Excel file when the file is closed , I get "1/1/2009" in the result set.

Why is there inconsistency with importing data from this Ole Data Source?

Thanks
Kit